Community Forums

jbhobbs54 · 06-21-2022, 04:30 AM

Have you checked the thermostat? I had one that failed and it stuck closed instead of open like they are supposed to. The actual guts failed and came apart.

1972VWbus · 01-28-2023, 04:41 PM

Curious did this get resolved? If so what did you do?

Before one in a similar situation feels the need to pull the radiator have a look behind the AC condenser/oil cooler you might be in for a surprise. I had to replace my AC condenser/oil cooler and low & behold...

Pics of the radiator: (before & after cleaning)

https://www.gmt400.com/threads/conde...r.59140/page-6

I'm willing to bet many in similar situation ended up spending big bucks on radiator replacement when in reality it only needed radiator fin cleaning. Use a 'Radiator Genie' from the backside to flush out annually.

Phair · 01-29-2023, 02:14 PM

After leaving the hotness of Utah and co, the issue stopped, except once during a long uphill in the Rockies ..

1972VWbus · 01-29-2023, 09:48 PM

Quote:

Originally Posted by Phair

After leaving the hotness of Utah and co, the issue stopped, except once during a long uphill in the Rockies ..

I'd bet the radiator tube fins just need cleaning out. If you use the 'Radiator genie' you can snake it up under the fan shroud on the backside lower end. Lift it off the (2) clips. Then use the Genie to clean from behind flushing to the front.

moisheh · 01-30-2023, 08:59 AM

Flushing an old rad is a waste of time. You need a recore. A good rad shop could build a thicker rad. Is there anything out front that can block airflow
I.e. a bike,bug screen spare tire? Get a new clutch fan. A good one. Not an important

1972VWbus · 01-30-2023, 08:04 PM

Quote:

Originally Posted by moisheh

Flushing an old rad is a waste of time. You need a recore. A good rad shop could build a thicker rad. Is there anything out front that can block airflow
I.e. a bike,bug screen spare tire? Get a new clutch fan. A good one. Not an important

Not talking of re-coring it. Cleaning the exterior tube fins out should be done first. More often than not it's overlooked due to the large AC condenser/oil cooler sitting smack dab in front of radiator.

If you look at the thread I posted you'll see how it's impossible to get at front of radiator with condenser in place.

BA-in-Mich · 02-01-2023, 05:07 PM

X2 Radiator recore. Sounds identical to the problems I had years ago. Recored and all is good.

craigd853 · 02-01-2023, 05:50 PM

Quote:

Originally Posted by Phair

Hi,
We are traveling with an old Chevy 454, on a 28' motorhome from 1991. Since Texas with more than 90° a lot of wind and some steep climb (NM, Colorado, Utah) the engine is overheating ... We removed the AC (which was not working) and added two fans (with a switch), and even like that it's still overheating.
So our 2nd guess was the fan clutch which was changed last year (around 6,000 miles ago), and even when the engine is hot, it seems to run freely ...
My questions are :
* Is it possible that the fan clutch broke that fast ?
* What is a correct speed/RPM when climbing ?

Hello and sorry for your issues. Like other folks have said about making sure the radiator fins are clean and there is no dirt between the radiator and the condensor is the cheapest fix first. My guess is that the radiator or thermostat is clogged. Radiators clog from the bottom up and your radiator is over 21 years old. This is only an assumption on my part but I'm assuming you have not owned it since new. So there's no telling what happened before you had it. From your description of when and how it over heats I would seriosly consider thinking about replacing the raditator. When it does clog and you can't tell from looking at it, you lose efficiency especially when climbing hills and when it's hot out. Good luck and hope you figure it out.

BA-in-Mich · 02-02-2023, 04:52 AM

With my radiator, the recore place showed me the old core. The inside had a white coating on it. The main issue he told me was it was a car radiator sized up to fit the motorhome. It was a 4 core with 3/8" tubes in it. He kept it a 4 core but sized up the tubes to 5/8". It runs at a constant 180* now.